Air conditioning



June 29, 1943. R. B. P. CRAWFORD 2,323,122

AIR CONDITIONING Filed Nov. 8, 1940 Patented June 29, 1943 UNITED STATES PATENT OFFICE AIR CONDITIONING Robert B. P. Crawford, Washington, D. C.

Application November 8, 1940, Serial No. 364,925

Claims.

This invention relates to air conditioning and is particularly directed to the provision of method and apparatus for the conditioning of air by contact with a chemical dehumidifying agent.

A principal purpose of the invention is to provide for the effective release of heat absorbed by chemical dehumidifying agents.

A further purpose of the invention is the effective utilization of the heat-absorbing capacity of underground water-bearing strata for the conditioning of air.

A further purpose of the invention is the provision of a method and apparatus whereby the cooling and dehumidification of a stream of air may be carried out in heat transfer relation with underground water-bearing strato.

Additional purposes and advantages of the invention will be apparent from the following description.

Broadly speaking, the invention comprises method and apparatus whereby a stream of air to be conditioned is brought into direct contact with an extended surface of a hygroscopic solution in an underground zone in heat transfer relation with water-bearing strata capable of absorbing heat at the desired temperature level of the air.

Preferably this is effected by means of a water permeable tunnel piercing a water-bearing stratum of sand or gravel. Within this tunnel is positioned a cooling and dehumidifying chamber constructed for the passage of air therethrough in contact with a dehumidifying chemical on the inside and in heat transfer relation with water on the outside. Heat release is accomplished by upsetting the normal balance of the water table adiacent the tunnel whereby the warm water in the tunnel is displaced by cold water from the surrounding strata. The operating equipment and any supplementary contacting or heat transfer equipment which may be required are advantageously housed in the portals at each end of the tunnel. The chemical dehumidifying agent may be any hygroscopic solution or liquid, such as calcium chloride, zinc chloride, ethylene or polyethylene glycerol or the like. The invention is particularly adapted for use with viscous chemical solutions which do not change substantially in vapor pressure within the operating range of temperature.

The tunnel may be positioned in the ground above the water-bearing strata and the water in these strata tapped by sumpsdriven from the inlet and outlet portals, when the pressure in the water-bearing strata is sufficient to force the water through such sump and around the tunnel.

In order to illustrate the principles of the invention, it will be more particularly described with reference to the illustrative embodiment shown in the accompanying drawing in which: Fig. 1 is a semi-diagrammatic representation in sectional elevation of an air conditioning sys- 'tem embodying the principles of the invention;

Fig. 2 is a partial transverse section on the line 22 of Fig. l; and

Fig. 3 is a fragmentary representation in partial section of the outlet end of the dehumidifying and cooling chamber of Fig. 1.

In Fig. 1, II is the basement or ground floor of the structure to be conditioned. II is a water-bearing layer, I2 is a layer of hard pan or clay such as commonly surmounts such a waterbearing layer, I3 is a substrate of clay or stone and I4 is a water-bearing substrata.

i5 is the water permeable tunnel, constructed, for example, of concrete blocks i6 having perforations H for the passage of water. I! is the inlet portal from which the tunnel is dug and constructed and the spoil removed, and i9 is the outlet portal.

Mounted in tunnel I5 is a cylinder 20, preferably inclined slightly downward from the herizontal toward the inlet portal, and mounted;

for rotation, for example, on supporting rollers 2| (Fig. 2). Cylinder 20 is substantially smaller than the interior diameter of the tunnel to provide an annular water-filled space between the cylinder and the wall of the tunnel. Cylinder 20 is provided with longitudinal perforated vanes 22. The cylinder is rotated by means of motor 23 mounted in inlet portal l8.

Hygroscopic solution accumulating in sump 24 at the inlet end of the cylinder is pumped by pump 25 through pipe 28 to the outlet end of the cylinder from which it flows back to sump 24, being spread into an extended surface by the action of perforated vanes 22, rotating with cylinder 20, Cylinder 20 may be stationary and the hygroscopic solution spread out into an extended surface by means of vanes rotated within cylinder 20. -A predetermined and controllable portion of the hygroscopic liquid is circulatcal on the walls and vanes of the cylinder and then is blown into the space to be conditioned either directly or through suitable duct systems.

Water level 32 in inlet portal "it is kept low during operation by pumping water from sump 33, by means of pump 34 driven by motor 85 and shaft 38, through pipe 34 to dump 28 in outlet portal It. This raises the water level in i9 to 31 and the increased pressure causes water from it to ilow through orifices 38 into the annular space around cylinder 20. through which it flows at high velocity toward the inlet portal and into sump 33. The normal prevailing water level is indicated at 39, and the operating water level aftected by the transfer of water from sump 83 to portal I9 i indicated at 40. This sloping water level causes the cooler water in the water-bearing stratum to displace the warmer water in the annular space around the cylinder 20 through the openings ll.

Where additional cooling is desired, the water dump may be extended through sump II to dump at 42 in a circulating water stratum M, the point of dumping being controlled by valve 43. This displaces colder water from the upper part of the stratum l4 into sump 4| and portal l9.

To the extent that the warm water dumped at 42 is carried by circulation to sump 33 it will be adequately cooled by contact with the sand and gravel of stratum l4.

It will be obvious that the principle of the invention i not limited to the particular arrangement of strata or the particular form of the various elements of the system shown by way of example, but broadly comprises a method and apparatus whereby a stream of air to be conditioned is contacted with a hygroscopic solution in a subterranean zone in heat transfer relation with subterranean water-bearing strata.

I claim:

1. An air conditioning system comprising a subterranean channel permeable to ground water, a conduit extending through said channel, means for supplying a hygroscopic solution to the interior of said conduit, means for passing a stream of air through said conduit, and means for maintaining a higher ground water level at the outlet end of said subterranean channel than at the inlet end thereof to cause flow of ground water along said channel counter-current to the stream of air in said conduit.

2. An air conditioning system comprising a subterranean channel permeable to ground water,-

a conduit extending through said channel, means for supplying a hygroscopic solution to the interiorof said conduit, means (or passing a stream of air through said conduit, a sump at the inlet end of said channel to collect ground water, and means for transferring ground water from said sump to the outlet end of said channel to cause flow of ground water along said channel counter-current to the stream or air in said conduit.

3. An air conditioning system comprising a subterranean channel permeable to ground water, a conduit extending through said channel, means for supplying a hygroscopic solution to the interior of said conduit in heat exchang relation with ground water in said channel, a plurality of rotatable longitudinally extending vanes in said conduit for spreading said ygroscopic olution into an extended surface, and means for passing a stream of air through said conduit.

4. An air conditioning system comprising a subterranean channel permeable to ground water, a rotatable conduit extending through said channel, means for supplying a hygroscopic solution to the interior of said conduit in heat exchange relation with ground water in said channel, and means for passing a stream of air through said conduit.

5. An air conditioning system comprising a pair of spaced vertical shafts extending into the ground below the water table, a subterranean channel extending between said shafts, a conduit passing through said channel from the first to the second of said shafts and inclined slightly downward toward the first of said shafts, means for supplying a hygroscopic liquid to the interior of said conduit adjacent the second of said shafts, means for passing a stream of air through said conduit, and means for transferring ground wa 'ter from. the first of said shafts to the second of said shafts to cause flow of ground water along said channel counter-current to the stream of air in said conduit.

ROBERT B. P. CRAWFORD. 

